Why do those Thai characters display on the web page with a long tail?

Question

ด้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้дด็็็็็้้้้้็็็็้้้้้็็็็็้้้้้็็็็็้้้้้็็็็็้้้้้

I found some interesting characters just

Answer 1

What you have found is called Combining Characters or as common folk it call Zalgo.

It works because Unicode allows to combine characters by adding diacritic marks after character.

Any system that uses Unicode will work with these characters.